An overview of our efforts to elucidate the mechanistic details of the surface chemistry of hydrocarbons on transition metal surfaces will be presented. Particular emphasis will be placed on the similarities and differences between surface and organometallic systems, and on the relevance of this chemistry to catalysis. The methods developed in our laboratory for the clean production of catalytically-relevant but unstable surface moieties on well-characterized metal surfaces will be described, and the main thermal decomposition pathways of those intermediates will be discussed. An argument will be presented for the definition of catalytic selectivities based on subtle changes in the regioselectivity for early dehydrogenation rates. For instance, the unique ability of platinum in promoting isomerization and cyclization reactions appears to correlate with its preference to catalyze gamma-hydride elimination steps; nickel, in contrast, facilitates dehydrogenation at the alpha position, and catalyses hydrogenolysis instead. The additional mechanistic complications in hydrocarbon reforming under catalytic conditions introduced by the presence of strongly bonded carbonaceous deposits on the surface of the active catalyst will be addressed. The working reforming metal catalyst is likely to display a bifunctional character, with rapid hydrogenation-dehydrogenation steps taking place on the hydrocarbon-covered surface and more demanding skeletal rearrangement steps occurring on patches of bare metal. Finally, some details behind the imparting of enantioselectivity to metal catalysts via the adsorption of chiral modifiers will be introduced.